Phelps Dodge Sierrita Mine
Off-Site Monitor Well MH-12
Monitor well on public state land between tailings dam and Green Valley
Located approximately ¾ mile east of dam, approximately at top of dam
Sulfates and Dissolved Metals
Date |
Hardness as CaCO3 |
Calcium mg/l |
Magnesium mg/l |
Sulfate |
Arsenic mg/l |
Molybdenum |
TDS |
Alkalinity |
pH Units |
4/24/79 |
94 |
19 |
251 |
660 |
7.18 |
||||
7/12/79 |
193 |
44 |
572 |
1023 |
8.19 |
||||
12/17/79 |
85 |
17 |
143 |
550 |
7.32 |
||||
4/23/80 |
84 |
45 |
288 |
722 |
7.85 |
||||
10/20/80 |
89 |
18 |
178 |
563 |
7.73 |
||||
12/19/80 |
83 |
17 |
214 |
625 |
7.90 |
||||
4/29/81 |
193 |
42 |
559 |
1068 |
7.93 |
||||
9/18/81 |
130 |
2 |
223 |
752 |
7.53 |
||||
12/10/81 |
130 |
0 |
236 |
660 |
7.39 |
||||
4/28/82 |
139 |
4 |
263 |
690 |
7.20 |
||||
9/30/82 |
104 |
36 |
266 |
680 |
7.78 |
||||
9/25/97 |
285 |
58.6 |
860 |
1640 |
-- |
||||
2/26/98 |
310 |
60.7 |
860 |
1590 |
7.23 |
||||
6/30/98 |
334 |
61.7 |
880 |
1760 |
6.93 |
||||
4/04/01 |
321 |
65.9 |
980 |
1720 |
7.3 |
||||
12/02/03 |
342 |
67.3 |
1050 |
1860 |
-- |
||||
3/15/04 |
336 |
69.7 |
1040 |
1900 |
6.69 |
** Secondary standard set by EPA, not enforced in
Regulated Inorganic Chemicals
--not available--
Regulated Radioactive Chemicals
Date |
Gross Alpha pc/l |
Gross Beta pc/l |
Radium 226 pc/l |
Radium 228 pc/l |
Radon* 222 pc/l |
Uranium 234 pc/l |
Uranium 235 pc/l |
Uranium 238 pc/l |
Total Uranium mg/l |
12/02/03 |
5.3 ± 1.6 |
19.7 ± 4.7 |
0.5 ± 0.4 |
ND |
535 ± 45.9 |
2.7 ± 0.9 |
0.2 ± 0.2 |
0.9 ± 0.5 |
0.0045 |
3/15/04 |
4.9 ± 1.8 |
24.4 ± 4.2 |
0.5 ± 0.3 |
ND |
2.9 ± 0.7 |
ND |
ND |
1.0 ± 0.4 |
0.0042 |
MCLG** |
0 |
0 |
Ra 226 + Ra 228 = 0 |
None |
None |
None |
None |
0 |
|
MCL*** |
15 pCi/ltr |
4 mrem/yr |
Ra 226 + Ra 228 = 0 |
None |
None |
None |
None |
.03 mg/ltr |
|
* No standard set for Radon
** Maximum Contaminant Level Goal, 40 C.F.R. § 141.55.
***Maximum Contaminant Levels, 40 C.F.R. § 141.66(b) [for Ra-226+-228]; (c) [for gross alpha activity]; (d) [for beta particle and [photon radioactivity]; and (e) [for uranium].